Abstract: On the review bench today we have Scythe's Ashura
heatsink; this is a fairly standard tower cooler equipped with a 140mm
fan. The Ashura cooler stands 162mm tall, making it suitable
for full tower cases where AIO liquid coolers are often too
bulky.

On the review bench today we have Scythe's Ashura
heatsink; this is a fairly standard tower cooler equipped with a 140mm
fan. The Ashura cooler stands 162mm tall, making it suitable
for full tower cases where AIO liquid coolers are often too
bulky. It's relatively narrow footprint of 145x88mm means the Ashura
heatsink is less likely to interfere with adjacent mobo
components, memory modules and graphics cards.

The Ashura heatsink
ships with a single 140mm PWM fan that operates at 1300-800RPM,
moving upwards of 97CFM according to manufacturer specs. Noise output is modest at
full fan speed and downright whisper quiet at 800RPM. Scythe also include an extra set of wire fan brackets
so an additional 140/120mm fan (not included) can be mounted on the back of the
tower, if desired.

Weighing 750grams, the Scythe Ashura heatsink is built around six 6mm
diameter copper heatpipes which are soldered to a nickel plated copper base
plate, rather than being left exposed in the 'heatpipe direct touch' fashion. The heatpipes are swaged into the 121x145x50mm aluminum
fin stack and the two rows are offset just a little to
break up potential low airflow regions. The heatsink is capped with a
black anodized aluminum shroud for purely cosmetic reasons. The black plate presents
a clean visual appearance when looking through windowed case side panels, for
example.

Scythe's Ashura heatsink retails for about $45USD/CDN
and is compatible with AMD socket
AM2/AM3/FM1/FM2 processors and the full line of Intel LGA2011/1366/115x/775 CPUs.

The 140mm PWM fan
that ships with the Ashura heatsink is a Scythe "GlideStream 140 PMW", it uses sleeve
bearings. Two things are notable about this fan; 1) the top surface of each
impeller blade features a series of shallow slits which Scythe claim reduces air
resistance, 2) the eleven impeller blades are mounted on a relatively compact, 40mm diameter motor hub so more of the fan area is a "working surface".

The fan has its mounting holes spaced 105mm
apart, so technically it can also mount anywhere a 120mm fan can go. You'll also
notice in the photo below, the wire fan clips have no thumb tabs sticking out to
potentially contact the back of a videocard. The springy wire clips aren't
difficult to engage, so the lack of tabs simply adds to the heatsinks'
slim profile.

The heatsink fins are made from raw aluminum and feature a
series of six small "V" bends along the leading and trailing edges. These bends supposedly help break up laminar airflow which can reduce metal-to-air heat conduction.

Heatpipes are soldered to the copper base plate to ensure
good thermal conduction, however the heatsink Frostytech tested had visible gaps
at the edges of perhaps 40% of these joints. The glue visible around the
heatpipes is in fact from the application of the top aluminum cap
which supports the mounting bracket.

Multi-core processors can develop hot spots in regions
of the CPU die, so heat spreaders are generally considered more beneficial
than direct heatpipe contact systems because those hot regions can be conducted across multiple heatpipes. The trick is ensuring a thorough heatpipe-to-base plate solder joint.

Heatsink Mounting
Hardware

The Scythe
Ashura heatsink accommodates Intel socket LGA2011/1366/115x/775 processors and
AMD
socket AM2/AM3/FM1/FM2 CPUs. The Ashura ships with a metal rear motherboard support bracket, a variety of metal mounting brackets, associated hardware and an extra set of wire fan brackets. A small pack of grey thermal compound is also provided.

FrostyTech's Test Methodologies are outlined in detail here if you care to know what equipment is
used, and the parameters under which the tests are conducted. Now let's move
forward and take a closer look at this heatsink, its acoustic characteristics,
and of course its performance in the thermal tests!